Abstract
Arsenic (As) contamination has emerged as a serious public health concern worldwide because of its accumulation and mobility through the food chain. Therefore, the current study was planned to check the effect of Bacillus subtilis-synthesized iron oxide nano particles (Fe3O4 NP) on rice (Oryza Sativa L.) growth against arsenic stress (0, 5, 10 and 15 ppm). Iron oxide nanoparticles were extracellular synthesized from Bacillus subtilis with a desired shape and size. The formations of nanoparticles were differentiated through UV-Visible Spectroscopy, FTIR, XRD and SEM. The UV-Visible spectroscopy of Bacillus subtilis-synthesized nanoparticles showed that the iron oxide surface plasmon band occurs at 268 nm. FTIR results revealed that different functional groups (aldehyde, alkene, alcohol and phenol) were present on the surface of nanoparticles. The SEM image showed that particles were spherical in shape with an average size of 67.28 nm. Arsenic toxicity was observed in seed germination and young seedling stage. The arsenic application significantly reduced seed germination (35%), root and shoots length (1.25 and 2.00 cm), shoot/root ratio (0.289), fresh root and shoots weight (0.205 and 0.260 g), dry root and shoots weight (6.55 and 6.75 g), dry matter percentage of shoot (12.67) and root (14.91) as compared to control. Bacillus subtilis-synthesized Fe3O4 NPs treatments (5 ppm) remarkably increased the germination (65%), root and shoot length (2 and 3.45 cm), shoot/root ratio (1.24) fresh root and shoot weight (0.335 and 0.275 mg), dry root and shoot weight (11.75 and 10.6 mg) and dry matter percentage of shoot (10.40) and root (18.37). Results revealed that the application of Fe3O4 NPs alleviated the arsenic stress and enhanced the plant growth. This study suggests that Bacillus subtilus-synthesized iron oxide nanoparticles can be used as nano-adsorbents in reducing arsenic toxicity in rice plants.
Highlights
Introduction nal affiliationsArsenic (As)-polluted water is a serious problem in Pakistan [1], which is further aggravated by industrialization and agricultural practices [2]
Bacteria culture was centrifuged at 4000 rpm for 12 minutes and the culture supernatant was used for the synthesis of iron nanoparticles
Bacillus subtilis extract because it contains rereducing compounds which increase the synthesis of
Summary
Arsenic (As)-polluted water is a serious problem in Pakistan [1], which is further aggravated by industrialization and agricultural practices [2] It enters in the human body through inhalation, ingestion or skin absorption and affects different organs [3]. Rice is an essential staple food grown under flooded conditions; if irrigated with As-contaminated water, the same accumulates in different parts of plant tissues and is subsequently transported to the human food chain [4]. Various methods, such as physical, chemical and biological methods, have been practiced in order to remediate As from water.
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